LAS VEGAS — For 40 years, comedian Jerry Lewis and his muscular dystrophy telethon have been as much a part of Labor Day weekend as the start of school and the symbolic end of summer.

Now at 80, and swallowing 25 pills a day for his sagging health, Lewis is approaching his curtain calls dogged by disabled activists who contend the show is designed to evoke pity rather than empower the disabled.

Led by a former muscular dystrophy poster boy from Chicago, the activists scored what they call their “big triumph” last November as wheelchair-bound protesters ambushed Lewis in an appearance at the Harold Washington Library Center in Chicago.

As they interrupted his speech, Lewis reacted as he has for years to critics–denouncing them and then storming off the stage.

“They want me to stop the telethon because I make them look pitiful,” Lewis said, according to a recording made by an audience member. “What is more pitiful than this?”

The 21½-hour telethon–scheduled to air on some 190 stations nationwide starting Sunday night–moves to Las Vegas after a 12-year run in Hollywood. As they have for most Labor Days in the past 15 years, protesters plan to appear at several satellite telethon locations around the country including Los Angeles to denounce “the charity mentality.”

“Jerry Lewis has got to go,” said Mike Ervin, 50, a freelance writer and disability rights proponent. He has mockingly formed a group in Chicago called “Jerry’s Orphans” that plays off Lewis calling show participants “Jerry’s Kids.”

Ervin is distributing a documentary entitled “The Kids Are All Right,” which chronicles his years of dissent. Despite the protesters’ urgings, the telethon has not changed its ways and has not promoted accessibility for the disabled, better housing and employment possibilities, activists say.

“The concerns don’t seem to sink in,” said Andy Imparato, president of the American Association of People with Disabilities.

In an interview last week with the Tribune at the South Coast hotel-casino, Lewis said he has no intention of making peace with his detractors. He likened the idea of meeting with them to entertaining Hezbollah or insurgents in Iraq.

“Oh God, why should I?” he asked.

Supporters say Lewis has been unfairly targeted.

“He is worthy of a major, major pat on the back for a job well done,” said Steve Mikita, an assistant Utah attorney general who has a form of the disease.

Known as the “King of Comedy,” Lewis is more than a public face for muscular dystrophy fundraising. He is its driving force. How Lewis became linked with muscular dystrophy–the more common strain affects some 200,000 Americans–remains a mystery. Lewis refuses to discuss it.

“It was personal, private,” he told reporters last week.

Muscular dystrophy is a catchall term for more than 30 genetic diseases that weaken and degenerate muscles. In all, about 1 million Americans are affected–the worst cases often being boys who grow unable to walk or breathe without a respirator.

Lewis’ goal has been to fund research to find a cure; he has raised an astounding $1.35 billion. While a cure remains elusive, telethon funds spearheaded research that identified the gene and protein defining the disease and ultimately helped lengthen life. Charity watchdog groups give the Muscular Dystrophy Association high marks.

Through four decades, Lewis has never missed a telethon, even while suffering from an addiction to painkillers. In recent years, a steroid used to treat pulmonary fibrosis, a chronic lung ailment, ballooned his weight.

Never one for political correctness, Lewis has been prone to faux pas on the telethon.

But in 1990, Lewis went too far, disabled-rights activists said. In a Parade Magazine article, Lewis envisioned himself sitting in a wheelchair bound by muscular dystrophy.

“I realize my life is half, so I must learn to do things halfway,” he wrote. “I just have to learn to try to be good at being a half a person.”

Coming as the disabled movement was blossoming, Lewis became the bull’s-eye for activists. Chicagoans Ervin and his sister Cris Matthews–who had appeared as muscular dystrophy kids on a local television fundraiser in 1961–led the protest.

“The telethon gives a negative message about people with disabilities,” said Laura Hershey, once a “Jerry’s Kid” who organized a movement in Denver called “Tune Jerry Out.”

Lewis told the Tribune that in hindsight his Parade piece “would be different today.” Still, he refers to the activists as a tiny band of inconsequential troublemakers.

“I paid for their wheelchairs,” he said, speaking metaphorically about his work.

Like many families battling muscular dystrophy, Sophie Mitzel of Aurora is grateful for Lewis’ support. Decades ago she remembers participating in a fundraiser for the telethon.

Now, with her son Logan, 7, suffering from a form of the disease, Mitzel will volunteer for the third year locally in Chicago on the WGN telethon with 20 of her family and friends.

“I don’t know where we’d be without the tremendous help of Jerry Lewis,” she said.

Such backers can’t help but wonder how the telethon will survive without Lewis.

In the fast-paced electronic age, telethons are outdated and Lewis’ effort is the last big one. Amidst declining viewership, last year’s telethon generated $54.9 million in donations–an 8 percent drop.

Despite suffering a mild heart attack, Lewis was chipper this week as he scooted around in a motorized cart cracking his trademark jokes.

Dressed in a casual jogging jacket and wearing black slippers and no socks, Lewis seemed at peace with himself despite his critics.

“I really believed I have developed into a good man,” he said.